I have this exact situation. I'm moving to a new server and I could not get the transfer to work, so we moved thebackup drive over to the new server and I'm restoring the backups to the new box via the restore function. Any site using PHP is giving me this 505 error and I have absolutely no clue. Something that should have been easy has turned out to be a nightmare.

Can someone please advise what I need to do.

I've checked the file/folder permissions - they are all as they should be
I've checked the ownership of the files/folder - they are also as they should be the user name is the owner.